Biology subjects

Derr, K.

Publications and source records attributed to Derr, K..

3 recordsLinked to original sources

bioRxiv2026

A mammary-specific microfluidic device for studying post-radiotherapy vascular-immune cell interactions

Radiotherapy (RT) significantly improves outcomes and reduces the risk of recurrence in breast cancer. However, in patients that experience recurrence despite treatment, the irradiated breast tissue may create a pre-metastatic niche that promotes tumor cell infiltration. Because current models of metastasis lack key physiological and microenvironmental cues, we developed a mammary vasculature-on-chip (MVoC) to model how the vasculature responds to RT and impacts immune and tumor cell behavior in mammary tissue. Murine and human MVoCs incorporated endothelial cells (ECs) cultured under physiologic shear stress and mammary-specific fibroblasts to mimic the vascular-fibrous stroma interface. MVoCs exhibited a transient, acute response to RT that led to a persistent phenotypic shift. Neutrophils, which play key roles in pre-metastatic niche formation, adhered more to irradiated ECs and induced persistent damage to the endothelial barrier, preventing recovery. Neutrophils also significantly increased tumor cell adhesion to the endothelium in MVoCs. These findings demonstrate that MVoCs can be used to study RT-induced pre-metastatic niche formation and suggest a positive feedback loop between damaged ECs and immune cell activation that may facilitate tumor cell colonization. MVoCs provide a biologically relevant approach to probe molecular and cellular interactions, improving translation toward developing novel therapies that improve patient outcomes.

cancer biology↗

bioRxiv2025

Projection-defined ventral tegmental area neurons exhibit distinct fentanyl-induced molecular and functional adaptations that differentially support drug-context associations

RationaleSynthetic opioids like fentanyl are contributing to unprecedented overdose rates, yet the neural circuitry underlying fentanyl-associated behaviors remains poorly understood. The ventral tegmental area (VTA) projects to both the nucleus accumbens (NAc) and prefrontal cortex (PFC), forming distinct pathways that are implicated in drug-cue associations, though their specific roles in fentanyl-context encoding are not well defined. ObjectivesThis study aimed to determine how VTA-NAc and VTA-PFC circuits contribute to fentanyl-context associations, and to assess the role of downstream dopamine receptor signaling in fentanyl context-seeking. MethodsMale and female mice underwent fentanyl conditioned place preference (CPP; 0.2 mg/kg). We locally inhibited dopamine D1 or D2 receptors in NAc or PFC during CPP expression. We used fiber photometry calcium imaging to measure activity in VTA-NAc and VTA-PFC projection neurons, and chemogenetic inhibition to suppress activity during CPP expression. ResultsFentanyl CPP expression was attenuated by blocking D1 but not D2 receptors in PFC, and D2 but not D1 receptors in NAc. We found both VTA-NAc and VTA-PFC exhibited increased calcium activity during fentanyl exposure and during entries to the fentanyl-paired context. We further identified a functional role for VTA-NAc, as chemogenetic inhibition of VTA-NAc, but not VTA-PFC, reduced fentanyl context-seeking. ConclusionsWhile both VTA-NAc and VTA-PFC pathways are recruited by fentanyl exposure, fentanyl context-seeking relies on different downstream dopamine receptors in NAc vs PFC. Further, activity in VTA-NAc functionally supports the expression of fentanyl CPP. Together, these findings indicate that VTA circuits differentially contribute to fentanyl context-seeking.

neuroscience↗

bioRxiv2024

Identification of potent HSV antivirals using 3D bioprinted human skin equivalents

Herpes simplex virus (HSV) infection has worldwide public health concerns and lifelong medical impacts. The standard therapy, acyclovir, has limited efficacy in preventing HSV subclinical virus shedding, and drug resistance occurs in immunocompromised patients, highlighting the need for novel therapeutics. HSV manifests in the skin and mucosal epithelium. Here, we found acyclovir significantly less effective in skin-derived keratinocytes than donor-matched fibroblasts. To recapitulate in vivo tissue architecture, we 3D bioprinted human skin equivalents (HSE) in a 96-well plate format amenable for antiviral screening and preclinical testing. We screened a library of 738 compounds with broad targets and mechanisms of action and identified potent antivirals, including 23 known or experimental HSV treatments, validating the translational relevance of our assay. Unlike acyclovir, antivirals against HSV helicase/primase or host replication pathways displayed similar potency across cell types and donor sources in 2D and 3D models. Our 3D bioprinted platform allowed for integrating patient-derived cells and incorporating genetic variability early in drug development. The reduced potency in keratinocytes helps explain the limited benefit acyclovir and its congeners play in reducing sexual transmission. These data indicate that the 3D bioprinted HSE assay platform provides a more physiologically relevant approach to identifying potential antivirals for HSV. One Sentence SummaryHigh-throughput screen using 3D bioprinted human skin equivalents to identify antivirals against HSV and evaluate cell-type specific effects.

bioengineering↗